Solid electrolytic capacitors (e.g., tantalum capacitors) are typically made by pressing a metal powder (e.g., tantalum) around a metal lead wire, sintering the pressed part, anodizing the sintered anode, and thereafter applying a solid electrolyte. Intrinsically conductive polymers are often employed as the solid electrolyte due to their advantageous low equivalent series resistance (“ESR”) and “non-burning/non-ignition” failure mode. Recently, conductive polymer slurries that contain a complex of poly(3,4-ethylenedioxythiophene) and polystyrenesulfonic acid (“PEDT:PSS complex”) have been employed as a solid electrolyte material due to their ability to handle high voltages, such as experienced during a fast switch on or operational current spike. While some benefits have been achieved, one problem with polymer slurry-based capacitors is that their capacitance is highly temperature dependent. For example, the capacitance tends to drop significantly at low temperatures (e.g., −55° C.), which can prevent the use of such capacitors in cold temperature environments, such as often experienced in aerospace or military applications.
As such, a need currently exists for a solid electrolytic capacitor having improved stability at a wide variety of different temperatures.